Re: Help with some clever bit operations

Robert Cummings wrote: > On Tue, 2006-06-13 at 06:22, Jochem Maas wrote: >> My brain needs a crutch when trying doing this kind of thing >> (normally I only write hex number literally when dealing with bitwise stuff - >> the conversion stuff still makes my head spin) - this is what this table is for: >> >> 128 64 32 16 8 4 2 1 >> 1 0 1 1 0 1 0 1 >> 0 1 0 1 1 1 0 0 >> 0 0 0 0 1 1 1 1 >> >> and then I did this - hopefully it shows what you can/have to do: >> >> <?php >> >> // set some values >> $oldval = 128 + 32 + 16 + 4 + 1; // 10110101 >> $update = 64 + 16 + 8 + 4; // 01011100 >> $mask = 8 + 4 + 2 + 1; // 00001111 > > You could just do the following: > > $oldval = bindec( '10110101' ); > $update = bindec( '01011100' ); > $mask = bindec( '00001111' ); when I was writing the reply I played with about 5 different conversion funcs - pretty everything expect bindec() !!! I guess i was being lazy - but then I alway think directly in hex numbers when doing bitwise stuff (at least I use hex notation for the constant value that I almost invariably end up creating) anyway cheers for the lightbuld moment :-) > > Cheers, > Rob.